Accurately calculating hydrogeological parameters is crucial for evaluating and managing groundwater resources. Pumping tests are primarily used to obtain aquifer parameters, the accuracy of which directly influences the assessment of regional hydrogeological conditions, as well as the subsequent development, utilization, protection, and management of groundwater resources. Traditional unsteady flow methods are limited by subjective influences and non-uniqueness in parameter determination, resulting in aquifer parameters that are dependent on the estimation method and observation well locations. This presents a significant challenge for optimal parameter selection. In this study, a weighted joint curve method (WJCM) based on Theis equation and optimization theory was developed that simultaneously considers both the pumping and recovery stages of field tests. The WJCM can be applied to determine unique aquifer parameters in pumping tests involving multiple observation wells and can be implemented rapidly using Excel. Actual pumping test data in a confined aquifer were used to compare results obtained from the proposed method with those obtained from three traditional parameter estimation methods. The results indicate that the WJCM produces reliable results and unique parameters, is highly efficient, and is easily implemented. These findings have theoretical and practical implications for pumping test parameter inversion, relevant software development, and the evaluation and management of groundwater resources.